Testing system and method using electromagnetic near field measurements

ABSTRACT

A system, method and computer readable medium are provided. One system includes a transmit antenna, at least one receive antenna, and a controller configured to operate the transmit antenna and the at least one receive antenna to acquire coupled signal information from a device under test. The system also includes a processor configured to approximate a shape of a structure within the device under test using changes in resonance determined from the coupled reflected signal information and caused by different materials forming the structure.

BACKGROUND

Handheld or mobile computers are widely used, such as in different fieldmobility environments. For example, these computing devices may be usedby mobile field service and transportation workers to allow differenttypes of mobile operations, such as in-field computing, barcodescanning, and communication with remote external devices, among others.These devices are becoming increasingly more advanced and includeadditional functionality for use in different operating environment.

These computing devices typically include communication systemsconfigured for operation in a particular area. For example, one or moredifferent antenna arrangements or configurations may be provided forwireless communication using these devices. The antenna configurationsmay include different shapes or sizes of antenna that are designed tocommunicate over particular frequency bands. Thus, an antenna optimizedfor communication in a particular region (e.g., communication using U.S.frequency bands) may not operate well, or at all, in other regions(e.g., communication using European or South American frequency bands).

It is often difficult, and sometimes not possible (such as when anantenna is installed in an assembled housing) to determine whether animproper antenna has been installed within a particular device. Forexample, due to inexperience or inability to view an installed antenna,determining manufacturing and assembly issues with the antenna can bevery challenging, such as when the wrong antenna is installed within adevice (e.g., European antenna installed in a device to be used in theU.S.). Without opening the device to visually identify the antenna thatis installed, complex and expensive testing equipment, such as VectorNetwork Analyzers (VNAs) must be used.

Thus, there is needed a way to efficiently and accurately determine thetype of antenna installed within a device or other structures within thedevice without opening the device or using expensive test equipment.

SUMMARY

To overcome these and other challenges, aspects of broad inventiveprinciples are disclosed herein.

In one embodiment, a system is provided that includes a transmitantenna, at least one receive antenna, and a controller configured tooperate the transmit antenna and the at least one receive antenna toacquire coupled signal information (e.g., electromagnetically coupledsignal power) from a device under test. The system also includes aprocessor configured to approximate a shape of a structure within thedevice under test using changes in resonance determined from theacquired coupled signal information caused by different materialsforming the structure.

In another embodiment, a method for determining a shape of a structureis provided. The method includes measuring coupled signal power from areceive antenna, wherein the coupled signal power is measured in anelectromagnetic (EM) near field, and determining detuning effects fromthe received coupled signal power. The method also includes identifyingmaterials causing the detuning effects and approximating a shape of thestructure of interest using the identified materials.

In another embodiment, a computer-readable storage medium includesexecutable instructions capable of configuring one or more processorsfor measuring received power of coupled signals from an antenna inproximity to a structure of interest, wherein the coupled signals aremeasured in an electromagnetic (EM) near field, and determining detuningeffects based on the received power of the coupled signals. Thecomputer-readable storage medium further includes executableinstructions capable of configuring one or more processors foridentifying materials causing the detuning effects and approximating ashape of the structure of interest using the identified materials.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a testing system in accordancewith an embodiment.

FIG. 2 is a schematic diagram of a testing system in accordance with oneembodiment.

FIG. 3 is a diagram illustrating a testing system in combination with adevice under test in accordance with an embodiment.

FIG. 4 is an illustration of electromagnetic energy.

FIG. 5 is a diagram illustrating a receive antenna in accordance with anembodiment.

FIG. 6 is a diagram illustrating a receive antenna in combination with adevice under test in accordance with an embodiment.

FIG. 7 is a graph illustrating a Return Loss or S11 of a receive antennain free space, measured by a Vector Network Analyze.

FIG. 8 is a diagram illustrating Return Loss of receive antennas atdifferent locations of a device under test in accordance with anembodiment.

FIG. 9 is a graph illustrating Return Loss measured at the differentlocations of FIG. 8.

FIGS. 10A and 10B illustrate displays of approximate shapes ofstructures determined in accordance with an embodiment.

FIG. 11 illustrates a method for approximating a shape of a structure inaccordance with an embodiment.

DETAILED DESCRIPTION

The exemplary embodiments described herein provide detail forillustrative purposes and are subject to many variations in structureand design. It should be appreciated, however, that the embodiments arenot limited to a particularly disclosed embodiment shown or described.It is understood that various omissions and substitutions of equivalentsare contemplated as circumstances may suggest or render expedient, butthese are intended to cover the application or implementation withoutdeparting from the spirit or scope of the claims. Also, it is to beunderstood that the phraseology and terminology used herein is for thepurpose of description and should not be regarded as limiting. The terms“a,” “an,” and “the” herein do not denote a limitation of quantity, butrather denote the presence of at least one of the referenced object. Itwill be further understood that the terms “comprises” and/or“comprising,” when used in this specification, specify the presence ofstated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof.

Furthermore, as will be appreciated by one skilled in the art, aspectsof the present disclosure may be embodied as a system, method, orcomputer program product. Accordingly, aspects of various embodimentsmay take the form of an entirely hardware embodiment, an entirelysoftware embodiment (including firmware, resident software, micro-code,etc.) or an embodiment combining software and hardware aspects that mayall generally be referred to herein as a “circuit,” “module” or“system.” In addition, aspects of the present disclosure may take theform of a computer program product embodied in one or more computerreadable medium(s) having computer readable program code embodiedthereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM) or similar DVD-ROM andBD-ROM, an optical storage device, a magnetic storage device, or anysuitable combination of the foregoing. In the context of this document,a computer readable storage medium may be any tangible medium that cancontain, or store a program for use by or in connection with aninstruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing. Computer program code for carrying out operations for oneor more embodiments may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

At least some of the present disclosure is described below withreference to flowchart illustrations and/or block diagrams of methods,apparatus (systems) and computer program products according toembodiments described herein. It will be understood that each block ofthe flowchart illustrations and/or block diagrams, and combinations ofblocks in the flowchart illustrations and/or block diagrams, can beimplemented by computer program instructions. These computer programinstructions may be provided to a processor of a general purposecomputer, special purpose computer, or other programmable dataprocessing apparatus to produce a machine, such that the instructions,which execute via the processor of the computer or other programmabledata processing apparatus, create means for implementing thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

Handheld or portable computing devices can be used in many differentapplications. Accordingly, while various embodiments may be described inconnection with testing or verifying components for a device for use ina particular environment, the various embodiments are not so limited.For example, various embodiments may be used to test or verify differentcommunication components within a device, such as different antennaarrangements, as well as other structures therein.

When manufacturing and assembling computing devices, such as handheld orportable computing devices, different types of antenna may be installedwithin different configurations of the handheld or portable computingdevices. For example, different antennas are used for communication indifferent areas (e.g., U.S., Europe, South America, etc.) Duringassembly, a wrong type of antenna may be installed or wiring in thewrong orientation may be connected within the handheld or portablecomputing devices. For example, due to different factors, such as lackof experience or fatigue, an assembler may install the incorrect antennawithin a particular handheld or portable computing device. As such, adevice configured to operate in one region having particular operatingfrequency band requirements may have installed therein an antennaconfigured to operate in another region having different operatingfrequency band requirements. As a result, the device may not operate orperform sub-optimally, resulting in the return or exchange of thedevice.

Some embodiments of the present application describe systems and methodsto test or verify the internal configuration of a device, such as theconfiguration of one or more antennas installed within the device. Inone embodiment, one or more electromagnetic (EM) probes operating usingnear-field EM transmissions are configured to scan a device (e.g.,product) under test to determine the configuration or arrangement ofcomponents in the device. The resonance frequency and magnitude of theEM probe varies when in proximity to material of different dielectricproperties. The systems and methods monitor the resonance changes toestimate the material properties in proximity to the probe. In someembodiments, a system includes a set of EM probes to scan a device anddetermine certain properties and characteristics of the componentswithin the device, such as of different metal structures (e.g.,antennas). Thus, a user can verify or confirm, for example, the type ofantenna or wiring arrangement within the device. In some embodiments,the verification or confirmation identifies manufacturing or assemblydefects of the device without opening the device or powering on thedevice.

It should be noted that the testing or scanning system and the deviceunder test are referred to herein for ease of illustration. However, itshould be understood that the system and device under test may beconfigured as any type of testing apparatus for use in testing orscanning different devices.

One embodiment of a testing system 100 is shown in FIG. 1. The testingsystem can comprise a transmitter 102 having one or more transmitantennas 104 and a receiver 106 having one or more receive antennas 108.It should be noted that although one transmit antenna 104 and sixreceive antennas 108 are illustrated, the system 100 can compriseadditional transmit or receive antennas 104, 108 or fewer receiveantennas 108. In one or more embodiments, the receive antennas 108 arearranged in an array, which may be symmetrical or asymmetrical. Forexample, although the receive antennas 108 are shown in a generallyrectangular array configuration, the receive antennas 108 may bearranged or aligned to form different sized and shaped arrays as desiredor need, such as based on the device under test. In various embodiments,the receive antennas 108 in combination with the transmit antenna 104can form one or more EM probes to verify manufacturing and/or assemblingdefects or issues. In some embodiments, such as when used in fieldoffices or service departments, technicians can use the testing system100 to scan a product and determine if radio performance degradation iscaused by antenna failure. In other embodiments, the testing system 100can be used to scan wire routing inside the plastic housing of aproduct.

The receive antennas 108 are positioned in proximity to a device 110,such as a product under test that includes an area of interest 112(illustrated in dashed line corresponding to an antenna installed withinthe device 110). As described in more detail herein, by positioning thearray of receive antennas 108 in proximity to the area of interest 112(illustrated as adjacent to and over the area of interest 112), thedielectric properties of the material in proximity to each of thereceive antennas 108 can be estimated. Using the estimation of thedielectric properties, a rough approximation of the shape of thematerial can be determined, such as corresponding to the shape of aparticular antenna 114 within the device 110.

In some embodiments, different arrangements of receive antennas 108 maybe provided depending on the particular components to be scanned withinthe device 110. In one embodiment, the receive antennas 108 are arrangedbased on the expected shape or configuration of the different types ofantennas 114 that may be present within the device 110. In this way, thereceive antennas 108 can be used to estimate the dielectric property ofthe material of the antenna 114 within the device 110 to determine theapproximate shape of the antenna 114. By determining the approximateshape of the antenna 114, verification or confirmation that the correctantenna is installed with the device 110 may be performed, such as bymatching the expected shape to the estimated shape. It should be notedthat in some embodiments the matching process may be performed manuallyby a user comparing the determined estimated shape of an antenna 114 todefined known shapes of antenna that may have been installed in thedevice 100. In other embodiments, the matching process may be performedautomatically using a shape matching process using shape templatescorresponding to known antenna configurations. In these embodiments,user verification may be performed by visually confirming the match. Instill other embodiments, a semi-automatic process may be performed thatincludes user intervention during the matching, such as modifyingparticular borders of an estimated shape to determine a match.

It should be noted that in some embodiments, if a match is not found,notification may be provided. For example, in such a case, the system100 may be improperly operating or the antenna 114 may be completelyincorrect, such as being an antenna for installation in an entirelydifferent product.

The testing system 100 can also comprise a controller 116 coupled to thetransmitter 102 and receiver 106. It should be noted that any type ofcommunicative or operative coupling may be used, such as any type ofwireless or wired communication. The controller 116 is configured tocontrol the operation of the transmitter 102 and receiver 106, such asto control the transmissions by the transmit antenna 104 and thereception by the receive antennas 108. In one embodiment, the controller116 is a transmit and receive controller configured to control theradio-frequency (RF) pulses sent to the transmit antenna 102 and thecommunication of signals received by the receive antennas 108.

The testing device 118 can further comprise a processor 118 coupled tothe controller 116. As described in more detail herein, the processor118 can control the operation of the controller 116 to transmit andreceive as desired or needed. The processor 118 is also configured invarious embodiments to process received signal information, such as todetermine and monitor the resonance changes in the signals received bythe receive antennas 108 to estimate the material properties inproximity to each of the receive antennas 108. Additionally, a memory120, which may be any type of electronic storage device, can be coupledto the processor 118 (or form part of the processor 118). The processor118 may access the memory 120 to obtain antenna configurationinformation that can be used to verify the type of antenna 114 withinthe device 110, which may be performed manually, automatically, orsemi-automatically as described herein.

The testing system 100 can comprise a display 122 and user input device124 coupled to the processor 118 to allow user interaction with thetesting system 100. For example, the display 122 can allow visualconfirmation or user guidance to confirm the type of antenna 114 withinthe device 110, which may include receiving one or more user inputs atthe user input device 124 (e.g., keyboard, mouse, touchpad, etc.). Insome embodiments, the display 122 and user input device 124 may beintegrated, such as in a touchscreen display device.

While FIG. 1 illustrates a particular connection arrangement of thevarious components, a skilled artisan would appreciate the fact thatother connection arrangements may be made that are within the scope ofthis disclosure. Additionally, the various components may be housedwithin the same or different physical units and the separation ofcomponents within FIG. 1 is merely for illustration.

The testing system 100 can also comprise one or more communicationsubsystems to allow communication with external devices, such asnetworks, printers, etc. Thus, additional components may form part of orcommunicate with the testing system 100.

FIG. 2 schematically illustrates one embodiment of a portion of thetesting system 100 (generally showing the data acquisition portion). Inthe various embodiments, like numerals represent like parts. Asillustrated in FIG. 2, the transmitter 102 can comprise a transmitcircuit 200 coupled to the transmit antenna 104. The transmit circuit200 is configured to operate within a defined frequency range togenerate RF pulses for transmission by the transmit antenna 104. Forexample, in one embodiment, the transmit circuit 200 is configured tooperate in the 5 GHz to 10 GHz frequency range. However, it should beappreciated that the transmit circuit 200 can be configured to operateat different frequency ranges that may or may not overlap with the 5 GHzto 10 GHz frequency range. The transmit circuit 200 may be any type ofcircuit capable of generating pulses for transmission by the transmitantenna 104. For example, the transmit circuit 200 can be configured togenerate RF pulses based on the configuration of the transmit antenna104 or the particular application, such as the device 110 to be tested.The transmit source 200 in some embodiments is a power source thattransmits RF pulses to the transmit antenna 104.

It should be noted that although the transmit antenna 104 is illustratedas a loop antenna, different shapes and sizes of transmit antennas maybe used. Additionally, the relative positioning of the transmit antenna104 to the receive antennas 108 is merely for illustration.

The receiver 106 can comprises a plurality of tuning circuits 202illustrated as connected to a respective or corresponding antenna 108(e.g., patch antenna). In the illustrated embodiment, each of the tuningcircuits 202 can comprise a pair of parallel connected capacitors 204,206 that define a resonance range for use in monitoring the resonancechanges of received signals due to the detuning effects from the device106. Each of the tuning circuits 202 can comprise a diode 208 connectedbetween the pair of capacitors 204, 206. The diode 208 acts as arectifier to covert the received RF energy (alternating signal) from theRF coupled signals to a DC signal.

Each of the tuning circuits 202 can also comprise a voltmeter 210connected is parallel with the pair of capacitors 204, 206. Thevoltmeter 210 is configured to receive and measure the rectified DCsignal from the diode 208. For example, in illustrated arrangement, thevoltmeter 210 is configured to output the measured power of the RFsignal received by the receive antennas 108. Accordingly, each of thevoltmeters 210 outputs a measured value corresponding to the receivedpower of the antennas from a particular scanned region or the area ofinterest 112 (shown in FIG. 1). It should be noted, as discussed in moredetail herein, various embodiments, in addition to determining thecoupled signal power, also determine a frequency shift in the resonancecircuit coupled signals.

The receive antenna 108 can comprise concentric antenna elements 212,214 having aligned gaps 216, 218 respectively spaced 180 degrees aparton each of the antenna elements 212, 214. It should be noted that thesize and spacing of the antenna elements 212, 214, as well as the gaps216, 218 may be varied as desired or needed. Additionally, differenttypes of antenna arrangements and elements may be used and theconcentric antenna elements 212, 214 are shown merely for illustration.For example, the concentric antenna elements 212, 214 in someembodiments are configured to use near-field EM to determine materialdielectric properties. However, the detuning effects of other materialsmay be measured in other embodiments, such as of various materialstypically forming an antenna for radio communication.

In one embodiment, the antenna element 214 includes connectors 500(shown in FIG. 5) that allow for connection to the tuning circuits 202.It should be appreciated that different connectors and differentpositions of connectors may be implemented in one or more embodiments,and the connectors 500 are shown merely for illustration.

In various embodiments, the testing system 100, such as may beconfigured as a probe, becomes part of the antenna structure in the nearfield. For example, due to the reactive EM near field 400 (shown in FIG.4), the receive antenna 108 positioned in proximity to the device (110shown in FIG. 1) becomes part of the antenna structure of the antenna114 within the device 110. In particular, the device 110 under testbecomes part of the overall antenna structure.

The antenna structure formed by the combination of the testing system100 and the antenna 114 define a resonant structure that transfersguided wave to radiation. In the near-field, dielectric or metallicmaterial changes the resonance of the antenna structure, namely detuningthe antenna structure. The testing system 100 determines the differentdetuning effects caused by different materials in the device 110 toidentify or verify different structural properties or characteristics ofinterest. For example, metallic and magnetic materials within the device100 have the strongest detuning effects. Various embodiments, instead ofmeasuring noise, measure the coupled power and/or frequency shift of theresonance to determine the detuning effects, which allows foridentifying or verifying different structural properties orcharacteristics of interest, such as the shape of the antenna 114 withinthe device 110 (both shown in FIG. 1).

FIG. 3 illustrates a probe 300 of one embodiment positioned in proximityto a portion of the device 110. The probe 300 can comprise a pluralityof the receive antennas 108 within a housing that can be positioned, forexample, along or in contact with the housing 302 of the device 110(illustrated as a rear upper housing of the device 110 in FIG. 3).However, the probe 300 may be positioned at different locations of thedevice 100. In this embodiment, the probe 300 is positioned in proximityto a known location of the antenna 114 (shown in dashed lines) of thedevice 110. The shape of the antenna 114, once approximately determined,may be used to identify the type of antenna 114.

As can be seen in the illustrated embodiment, each of the receiveantennas 108 is positioned adjacent a different portion of the antenna114 due to the spaced apart relationship of the receive antennas 108.The spacing and arrangement of the receive antennas 108 may be varied toprovide different coverage areas as described in more detail herein. Forexample, instead of aligned rows of receive antennas 108, the receiveantennas 108 in each row (top and bottom rows as viewed in FIG. 3) maybe alternatingly offset from an adjacent receive antenna 108. In someembodiments, a stepwise arrangement of the receive antennas 108 may beprovided. As should be appreciated by the skilled artisan, differentantenna configurations and arrangements are encompassed by thisdisclosure.

As can be seen in FIG. 3, some of the receive antennas 108 cover all ofa portion of the antenna 114, while other cover only a portion of theantenna 114, and one (the bottom left receive antenna 108 in FIG. 3)does not cover any portion of the antenna 114. As a result of thedifferent positions of the receive antennas 108 and the materialsthereunder or adjacent thereto that have different dielectricproperties, such as metallic and magnetic materials, as wellnon-metallic and non-magnetic materials, different resonance changes maybe measured. In operation, the differences in the dielectric propertiesof the materials are measured using the receive antennas 108 based on adifference in receive power of coupled signals. Using the difference inreceived power, and optionally a frequency shift, an approximate orrough shape of the object of interest, in this example the antenna 114,within the device 100 can be determined. For example, different shapedportions of the antenna 114 cause resonance at different frequenciesthat can be detected using the testing system 100 (shown in FIG. 1).

As discussed in more detail herein, by measuring the received power bythe array of receive antennas 108, wherein one or more of the receiveantennas 108 has a different received power due to the dielectricproperties of materials in proximity to the particular receive antenna108, the estimated dielectric property of the materials may bedetermined. Using this information, which may also include adetermination of different resonance frequencies (resulting fromdifferent shaped materials in proximity to the receive antennas 108), anapproximate or rough shape of the structure defined by the materials maybe determined. For example, different shaped elements cause resonance atdifferent frequencies. Thus, in some embodiments, using a prioriinformation (e.g., empirical testing data) of the resonance frequenciescaused by different materials, the approximate or rough shape of theantenna 114 within the device 100 may be determined by identifying thelocations of the materials.

In operation, by measuring the received power detected by one or more ofthe receive antennas 108, resonant changes or detuning may be determinedas described herein. The amount of detuning varies based on theproperties of the material in proximity to the receive antenna 108within the near field, which in various embodiments, is the reactivenear field 400 (shown in FIG. 4). To determine the detuning, the one ormore antennas 108 may be positioned in proximity to the device 110 andalso may be moved to cover different areas of interest 112, such as ifthe object (e.g., antenna) to be detected is larger than the array ofreceive antennas 108. Thus, one or more probes 300 (shown in FIG. 3)formed from one or more receive antennas 108 each may be positioned instationary relationship to the device 100 and then moved after each areaof interest 112 is scanned. As illustrated in FIG. 6, a single receiveantenna 108 may be used to measure received power to determine theresonant changes or detuning. For example, the receive antenna 108 maybe scanned across the area of interest 112. The scanning may beperformed manually (e.g., moved by a user) or automatically, such aswhen the receive antenna 108 is part of a movable structure (e.g., amoveable probe support).

In one or more embodiments, the transmit circuit (shown in FIG. 2) isdriven to generate a probe antenna field having a strength that allowsfor detection of the transitions in the structure to be detected withinthe device 110 under test. For example, the device 110 may be a mobilecomputing device, such as an Intermec mobile computer available fromHoneywell Scanning and Mobility. However, the testing system 100 may beused to test for structures in any other device, such as devices havingantenna structures therein that are not visible once installed. Thedriven probe allows for the receive antenna 108 to detect, for example,the coupled power that is attempting to be delivered (coupled power infull resonance). In a radio application, antenna resonance may becharacterized by Return Loss or S11, where the S11 S-parameters describethe input-output relationship between or for a port in an electricalsystem. When antenna is at its full resonance, Return Loss is at minimumvalue. Thus, when measuring S11 of each receive antenna within thedevice 110, the testing system 100 can determine the approximate shapeof the structure within the device 110 without powering on the device110. For example, when the device 110 includes a radio antenna as theobject of interest, S11 of each receive antenna can be used to detectthe transitions on the radio antenna (e.g., transitions between metaland non-metal portions) and therefore used to determine the approximateshape of the radio antenna.

For example, the graph 700 shown in FIG. 7 illustrates a S11 curve 702that may be detected by one or more of the receive antennas 108. In thegraph 700, the horizontal axis represents frequency in GHz and thevertical axis represents magnitude in decibels (dB). The curve 702 has aprofile that may be used to determine resonant changes or detuningcaused by structures within proximity (e.g., within 1-10 millimeters) toone or more of the receive antennas 108. For example, a change in theshape (e.g., location of valley 704) of the curve 702 representative ofa change in received power or a location of the curve 702 representativeof a frequency shift may be used to determine the resonant changes ordetuning caused by the material within the device 110 in proximity tothe receive antennas 108. For example, different materials will causedifferent known detuning effects, which then may be used to reconstructan approximate shape of the structure causing the detuning detected bythe receive antennas 108.

For example, as illustrated in FIG. 8 one of the receive antennas 108 amay be located outside of the footprint of the device 110 (e.g., not inproximity to or abutting the housing 800 of the device 110), such as infree space. In this example, one of the receive antennas 108 b may belocated within the footprint of the device 110, and within the area ofinterest 112, but not in proximity to the structure of interest (theantenna 114 in this example), such as the polycarbonate material fromwhich the housing 800 is formed and in which the antenna 114 is located.Additionally, in this example, one of the receive antennas 108 c islocated within the area of interest 112 and in proximity to thestructure of interest (the antenna 114 in this example), which may beformed of copper (e.g., copper traces on a printed circuit board withinthe housing 800 and not visible to a user). Thus, in this example, thereceive antennas 108 a-108 c may be positioned in proximity to freespace, polycarbonate material, and copper on or within polycarbonatematerial. It should be noted that the location and spacing of thereceive antennas 108 are for illustration of this example, and differentlocations and numbers of receive antennas 108 may be used as describedherein.

In operation, when the transmit antenna 104 is activated, the receiveantennas 108 a-108 c detect coupled power from each of the regionscausing detuning effects to the respective receive antenna 108 a-108 c.It should be noted that when reference is made herein to on object beingin proximity to a receive antenna 108, this generally refers to theobject being within a distance of the receive antenna 108 such that thereceive antenna 108 is capable of measuring the detuning effect by theobject. In some embodiments, the receive antennas 108 are positionedsuch that no overlap of received signals from areas within the device110 exists. However, in other embodiment, overlap of the receivedsignals may exist.

The graph 900 shown in FIG. 9 illustrates S11 curves 902, 904 and 906corresponding to the antenna resonance coupled signals of the receiveantennas 108 a, 108 b and 108 c, respectively. In the graph 900, thehorizontal axis represents frequency in GHz and the vertical axisrepresents magnitude in decibels (dB). The curves 902, 904 and 906 maybe used to determine resonant changes or detuning caused by structuresin proximity to the receive antennas 108 a, 108 b and 108 c. Forexample, the curve 902 corresponds to the resonance or detuning of thereceive antenna 108 a. Thus, the curve 902 corresponds to a signalprofile for antenna resonance , in this example, for free space. Thefrequency response or S11 defined by the curve 902 may be used toidentify regions having no material in proximity to one or more receiveantennas 108. The curve 904 corresponds to a signal profile for antennaresonance, in this example, in proximity of a polycarbonate material.The frequency response and S11 defined by the curve 904 may be used toidentify regions having a polycarbonate material in proximity to one ormore receive antennas 108. As can be seen, the curve 904 is frequencyshifted with respect to the curve 902, as well as having a differentresonance. The frequency shift and change in S11 is a result of thedifference in the polycarbonate material versus free space, which can beused to determine resonance changes or detuning.

Similarly, the curve 906 corresponds to a signal profile for antennaresonance, in this example, for a copper material. The frequencyresponse defined by the curve 906 may be used to identify regions havinga copper material in proximity to one or more receive antennas 108. Ascan be seen, the curve 906 is frequency shifted with respect to thecurves 902 and 904, as well as having a resonance. The frequency shiftand change in S11 is a result of the difference in the copper materialversus the polycarbonate material and free space, which can be used todetermine resonance changes or detuning. Thus, as should be appreciated,different detuning effects are caused by different materials asevidenced by the frequency shifts and change in S11 between the curves902, 904 and 906.

The measured power from the receive antennas 108 are“electromagnetically coupled” from the transmit antenna 104. The betterthe resonance of the receive antenna (therefore the deeper the resonancein Return Loss or S11 chart), the higher the coupled power from thereceive antenna 108. When in proximity to dielectric or metallicmaterials, the receive antennas 108 will be detuned, therefore receivedpower will be lower than when antennas are in full resonance in FreeSpace.

It should be noted that the Return Loss or S11 graph is a pure antennameasurement using a Vector Network Analyzer. It is a direct measurementof the antenna resonance, by injecting power to an antenna and measuringthe ratio of the reflected power over injected power on the sameantenna. Thus, S11 graphs as illustrated herein show the antennadetuning effect when in proximity to various materials.

In various embodiments, using the determined locations of differentmaterials based on the different known detuning effects, an approximateshape of the structure causing the detuning detected by the receiveantennas 108 may be determined. For example, using plural receiveantennas 108, and knowing the material corresponding to the detuningeffect measured by each of the receive antennas 108, as well as thelocations of the receive antennas 108, allows for a rough or approximatedetermination of the shape of different materials causing the detuning.

Thus, for example, as shown in FIG. 10, a display 1000 illustrates ashape 1002 determined by identified metallic regions based on measureddetuning and the display 1004 illustrates a shape 1006 determined byidentified metallic regions based on measured detuning. As can be seen,while the shapes 1002 and 1004 are rough in dimensions, using a matchingtemplate or by visual comparison, the shapes 1002 and 1004 may bematched to known shapes of antennas (e.g., European and U.S. antennas).For example, while the shapes 1002 and 1004 may not be exactrepresentations of the structures, the differences between the shapes1002 and 1004 provide enough detail to distinguish between differenttypes of antennas. It should be noted that one or more shape featuresmay be searched for to match the shapes 1002 and 1004 with particularantenna shapes.

One or more embodiments include a method 1100 as illustrated in FIG. 11.With reference also to FIGS. 1-10, the method 1100 may be implemented orperformed using one or more systems described herein, such as thetesting system 100. The method 1100 includes positioning an array ofantennas in proximity to a device under test at 1102. For example, thereceive antennas 108 may be positioned in proximity to a housing of amobile computing device (e.g., adjacent a back surface of the mobilecomputing device adjacent an antenna therein). The method 1100 alsoincludes generating an EM field at 1104. For example, the transmitantenna 104 may be used to generate an EM field as described herein.

The method 1100 includes measuring received power in receive antennacoupled signals in the near field with the array of antennas at 1106. Invarious embodiments, each of the receive antennas measures power ofcoupled signals in proximity to the respective receive antenna. Adetuning based on the received power of the measured signals isdetermined at 1108. For example, change in magnitude of received poweror frequency shift in the resonance coupled signals may be used todetermine the detuning as described herein.

The method 1100 includes identifying materials causing the detuning at1110. The identification of materials may be determined based on knowndetuning effects caused by different materials. Once the differentmaterials are identified and based on the location of the receiveantenna detecting the power of coupled signals, an approximate shape ofa structure based on the identified materials may be determined at 1112.For example, the rough shape of an antenna within a housing may bedetermined.

Thus, by measuring received power using one or more receive antennas,various embodiments determine resonance changes specific to a materialhaving a particular shape of a structure, such as a particular shape ofan antenna.

It should be noted that the testing system 100 can comprise one or moremicroprocessor (which may be embodied as the processor 118) and amemory, such as the memory 120, coupled via a system bus. Themicroprocessor can be provided by a general purpose microprocessor or bya specialized microprocessor (e.g., an ASIC). In one embodiment, thetesting system can comprise a single microprocessor which can bereferred to as a central processing unit (CPU). In another embodiment,the testing apparatus 100 can comprise two or more microprocessors, forexample, a CPU providing some or most of the testing functionality and aspecialized microprocessor performing some specific functionality. Askilled artisan would appreciate the fact that other schemes ofprocessing tasks distribution among two or more microprocessors arewithin the scope of this disclosure. The memory can comprise one or moretypes of memory, including but not limited to: random-access-memory(RAM), non-volatile RAM (NVRAM), etc.

It should be noted that, for example, the antennas detected by thetesting system 100 can provide communication using different standardsand protocols, and as such, may have different shapes andconfigurations. For example, the wireless communication can beconfigured to support, for example, but not limited to, the followingprotocols: at least one protocol of the IEEE 802.11/802.15/802.16protocol family, at least one protocol of the HSPA/GSM/GPRS/EDGEprotocol family, TDMA protocol, UMTS protocol, LTE protocol, and/or atleast one protocol of the CDMA/IxEV-DO protocol family.

The flowcharts and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present disclosure. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems which perform the specified functions or acts, or combinationsof special purpose hardware and computer instructions.

The corresponding structures, materials, acts, and equivalents of anymeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to embodiments in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of embodiments of thedisclosure. The embodiments were chosen and described in order to bestexplain the principles of embodiments and practical application, and toenable others of ordinary skill in the art to understand embodimentswith various modifications as are suited to the particular usecontemplated.

The foregoing descriptions of specific embodiments have been presentedfor purposes of illustration and description. They are not intended tobe exhaustive or to limit the embodiments to the precise formsdisclosed, and obviously many modifications and variations are possiblein light of the above teaching. The embodiments were chosen anddescribed in order to best explain principles and practical applicationsthereof, and to thereby enable others skilled in the art to best utilizethe various embodiments with various modifications as are suited to theparticular use contemplated. It is understood that various omissions andsubstitutions of equivalents are contemplated as circumstances maysuggest or render expedient, but these are intended to cover theapplication or implementation without departing from the spirit or scopeof the claims. The following claims are in no way intended to limit thescope of embodiments to the specific embodiments described herein.

What is claimed is:
 1. A system comprising: a transmit antenna; at leastone receive antenna; a controller configured to operate the transmitantenna and the at least one receive antenna to acquire coupled signalinformation from a device under test based on a transmit signal of thetransmit antenna; and a processor configured to approximate a shape of astructure within the device under test using changes in resonancedetermined from the acquired coupled signal information and caused bydifferent materials forming the structure.
 2. The system of claim 1,wherein the at least one receive antenna comprises plural antennasarranged in an array and the structure within the device is a deviceantenna, the processor further configured to determine the approximateshape of the device antenna and identify a type of the device antennausing the determined approximate shape.
 3. The system of claim 1,wherein the coupled signal information comprises received powerinformation and frequency shift information, the processor furtherconfigured determine the approximate shape of the structure using thereceived power information and the frequency shift information.
 4. Thesystem of claim 3, wherein the processor is configured to use thereceived power information and frequency shift information to determineone or more materials of the structure.
 5. The system of claim 1,further comprising a display configured to display a visualrepresentation of the structure within the device under test.
 6. Thesystem of claim 5, further comprising a user input device configured toreceive a user input verifying the visual representation of thestructure as corresponding to a defined structure.
 7. The system ofclaim 1, wherein the structure comprises a radio antenna.
 8. The systemof claim 1, wherein the at least one receive antenna is configured tomeasure coupled signals in an electromagnetic (EM) reactive near field.9. The system of claim 1, wherein the transmit antenna and the at leastone receive antenna comprise a same antenna element.
 10. A method fordetermining a shape of a structure, the method comprising: measuringcoupled signal power from a receive antenna, the coupled signal powermeasured in an electromagnetic (EM) near field; determining detuningeffects from the received coupled signal power; identifying materialscausing the detuning effects; and approximating a shape of the structureof interest using the identified materials.
 11. The method of claim 10,further comprising using a location of a plurality of receive antennasthat measure the received power to determine a location of theidentified materials.
 12. The method of claim 10, further comprisingperforming a shape match using the shape from the approximating step.13. The method of claim 10, further comprising displaying the shape fromthe approximating step.
 14. The method of claim 10, further comprisingchanging a location of an array of receive antennas to measure differentin antenna resonance.
 15. The method of claim 10, wherein determiningthe detuning comprises using a frequency shift of the antenna resonance.16. A computer-readable storage medium comprising executableinstructions capable of configuring one or more processors for:measuring received power of coupled signals from a receive antenna inproximity to the structure of interest, the coupled signals measured inan electromagnetic (EM) near field; determining detuning effects basedon the received power of the coupled signals; identifying materialscausing the detuning effects; and approximating a shape of the structureof interest using the identified materials.
 17. The computer-readablestorage medium of claim 16, in which the executable instructions arefurther capable of configuring one or more processors to use a locationof a plurality of receive antennas that measure the coupled signals todetermine a location of the identified materials.
 18. Thecomputer-readable storage medium of claim 16, in which the executableinstructions are further capable of configuring one or more processorsto perform a shape match using the shape from the approximating.
 19. Thecomputer-readable storage medium of claim 16, in which the executableinstructions are further capable of configuring one or more processorsto display the shape from the approximating.
 20. The computer-readablestorage medium of claim 16, in which the executable instructions arefurther capable of configuring one or more processors to determine thedetuning using a frequency shift of the antenna resonance.